1. Field of the Invention
The invention relates to a novel seam-forming apparatus for connecting building panels in a continuous seam along adjacent side edges of two building panels in the construction of a building or like structure.
2. Prior Art and Background
It is known to construct continuous arch metal buildings with adjacent curved building panels which are seamed together at their adjacent edges. See e.g., U.S. Pat. No. 3,902,288.
In connection with seaming panels for such metal buildings, rotary seamer devices have been used. Such a device is disclosed, for example in U.S. Pat. Nos. 3,875,642 (which is hereby incorporated by reference as if fully set forth herein); 4,470,186 and 4,726,107. The rotary seamer devices connect or seam together the side edge portions of adjacent panels.
Each panel comprises a main portion from which the side edge portion extends vertically. A first panel includes an out turned side edge portion having an upwardly extending, outwardly turned flange portion and a down-turned terminal portion forming an inverted U-shaped channel. In other words, the first section extends upwardly from the panel, the second section extends outward laterally from the first section and a third section extends downward from the second section. A second panel includes an in-turned side edge portion having an inwardly turned flange portion disposed inside the U-shaped channel of the first panel. This in-turned side edge portion has a first section extending upwardly from the panel and a second section extending laterally inward from the first section. These sections of the second panel fit within the first and second sections of the first panel respectively. Such an arrangement is described, for example, in U.S. Pat. Nos. 3,967,430 and 4,505,084.
The panels themselves are generally curved but a panel may have both straight and curved portions. These building panels are described in U.S. Pat. No. 5,249,445 which relates to a method for forming arched roof, vertical walled self-supporting metal buildings.
Seamers such as those described in U.S. Pat. No. 3,875,642 are only capable of seaming either straight panel portions or curved panel portions. Such seamers are not able to seam panels that are both straight and curved. When attempting to utilize such a seamer on panels with both curved and straight portions, the seaming apparatus tends to "walk off" or dislodge from the seam particularly in transition areas when the panel changes from straight to curved or vice-versa. The dislodging causes damage to the panel and/or an improper seam.